1. Field of the Invention
This invention relates to a force sensor abnormality detection system for a legged mobile robot.
2. Description of the Related Art
A legged mobile robot is equipped with various sensors, including force sensors for detecting floor reaction forces, and robot motion is controlled based on the outputs of the sensors. Detection of whether or not the sensors are abnormal or faulty is therefore required. The prior art in this regard includes Japanese Laid-Open Patent Application No. 2003-211379 (e.g., paragraph 0072) which carries out detection of various errors (abnormalities) in a robot, and as one aspect of the detection, checks for error (abnormality) by determining whether the outputs of force sensors, specifically six-axis force sensors, are within the predetermined ranges.
The floor reaction forces acting on a legged mobile robot are indispensable parameters for controlling robot motion. Abnormality of the force sensors that detect these forces therefore needs to be appropriately detected. The prior art reference is limited to detecting sensor abnormality solely by determining whether sensor outputs are within the predetermined ranges. This is not altogether satisfactory from the viewpoint of detection accuracy because a sensor may be erroneously found not to be abnormal when a sensor output just happens to be passing through the predetermined range at the time of the determination.